Unexamined Patent Application Publication No. JP2001-263113 discloses a variable compression ratio device that changes the capacity of the combustion chamber of an internal combustion engine in order to change the compression ratio. This variable compression ratio device is provided with a multiple-link type variable mechanism that consists of multiple links, including a connecting rod connected to the piston so as to allow for a rocking motion. By rotation-driving a control shaft with an actuator, the rocking bearing of the control link is changed, which in turn changes the piston stroke.